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SEER Inquiry System - Report
Produced: 10/15/2025 11:54 PM
Question 20100052
Inquiry Details
References:
#1: ICD-O-3
#2: 2010 SEER Manual, 58. Rule 2, example 5
Question:
Reportability/Primary Site: What is the reportability status and primary site for a papillary carcinoma of thyroid tissue arising in an otherwise benign mature monodermal cystic teratoma (struma ovarii)? See Discussion.
Discussion:
Final diagnosis on the pathology report states, "One ovary showing mature monodermal cystic teratoma composed of thyroid tissue (struma ovarii)." The pathology COMMENT section states, "There is a 0.1 cm focus of thyroid tissue within the struma ovarii showing cytologic features of papillary carcinoma. This finding is likely of no clinical consequence."
Answer:
A papillary carcinoma of thyroid tissue in benign struma ovarii (mature cystic teratoma) is reportable.
These ovarian tumors contain a diversity of tissues including hair, teeth, bone, thyroid, etc. This reportable malignancy arose in thyroid tissue within the ovarian tumor. Code the primary site to ovary. Code to the actual organ in which the cancer arose. This will keep the case in the appropriate category for surgery coding, regional nodes, staging, etc.
Cancer Site Category:
N/A
Data Item Category:
Primary site
Other Category:
Reportability
Year:
2010
